Timing properties of MCP-PMT - Nagoya University · Timing properties of MCP-PMT K.Inami (Nagoya...

Timing properties of MCP-PMT

K.Inami (Nagoya university, Japan)

- Time resolution- Lifetime- Rate dependence- Applications (TOF, TOP)

Workshop on timing detectors at Saclay, 8-9 March 2007

2007/3/8-9 WS on timing detectors at Saclay 2

~400mm

Linear-array type photon detector

LX

20mm

Quartz radiatorx

y

z

IntroductionPhoton device for TOP counter

Cherenkov ring imaging counter with precise timing measurement (NIM A 440 (2000) 124)

Barrel PID upgrade for Super B factory

Single photon sensitivityGood transit time resolution (<50ps)Operational under 1.5T B-fieldPosition sensitive (~5mm)High detection efficiency

MCP-PMT is a best solution!


Input electron

HV

MCP channel

MCP-PMTMicro-Channel-Plate

Tiny electron multipliersDiameter ~10µm, length ~400µm

High gain~106 for two-stage type

→ Fast time responsePulse raise time ~500ps, TTS < 50ps

can operate under high magnetic field (~1T)Channel

~400µm

φ~10µm

Photo-cathode MCP plates Anode

Photon

Single photon


MCP-PMT for single photonTiming properties under B=0~1.5T parallel to PMT

HPK6 BINP8 HPK10 Burle25

bi-alkalimulti-alkalimulti-alkalimulti-alkaliphoto-cathode

2500360032003600Max. H.V. (V)

24261826Q.E.(%) (λ=408nm)

40434040Length-diameter ratio

251086Channel diameter(µm)50x50251811Effective size(mm)

71x715230.545PMT size(mm)

Burle2585011-501

HPK10R3809U-50-25X

BINP8N4428

HPK6R3809U-50-11X

MCP-PMT


105

106

107

0 0.2 0.4 0.6 0.8 1.2 1.4 1.61B (T)

Gai

nHPK6: 3.6kVBINP8: 3.2kVHPK10: 3.4kVBurle25: 2.5kV

Pulse responsePulse shape (B=0T)

Fast raise time (~500ps)Broad shape for BINP8

Due to mismatch with H.V. supply dividerNo influence for time resolution

Gain v.s. B-fieldSmall channel diameter shows high stability against B-field.Explained by relation btw hole size and Larmor radius of electron motion under B-field.

1ns

500ps 1ns

10mV20mV

1ns

2mV 2mV

HPK6 BINP8

HPK10 Burle25


Time responseTTS v.s. B-field

Small channel diameter shows high stability and good resolution.

TTS v.s. GainFor several HV and B-field conditions30~40ps resolution was obtained for gain>106

Hole size need <~10µmto get time resolution of ~30ps under 1.5T B-field.

20

40

60

80

100

120

0 0.2 0.4 0.6 0.8 1.2 1.4 1.61B (T)

TT

S (p

s)

HPK6: HV 3.6kVBINP8: HV 3.2kVHPK10: HV 3.6kVBurle25:HV 2.5kV

0

20

40

60

80

100

120

10 6 107

BINP8HPK6

HPK10Burle25

Gain

TT

S(ps

)

Single photon

Single photon


LifetimeHow long can we use MCP-PMT under high hit rate?

(Nucl. Instr. Meth. A564 (2006) 204.)

Light load by LED pulse (1~5kHz)20~100 p.e. /pulse (monitored by normal PMT)

55-60%65%XX OOAl protection

40-6037%Correction eff.

5deg13degBias angle

30~40ps29ps3~4x1061.5x1061.9x106Gain

34psTTS

16-20%19%21%Quantum eff. at 400nm

Multi-alkali (NaKSbCs)Photo-cathode

18mmφ11mmφEffective area

Russian (x5)HPK (x2)


0

0.5

1

0 10 20 30Integrated irradiation(x1013 photons/cm2)

Rel

ativ

e Q

.E.

λ=400nm

Time in Super-B factory (year)0 5 10 15

Relative Q.E. by single photon laser

Without Al protectionDrop <50% within 1yr.

With Al protectionLong lifeNot enough for Russian PMTs

Enough lifetime for HPK’s MCP-PMT with Al protection layer

Lifetime - Q.E. -

HPK w/ AlHPK w/o AlRussian w/ AlRussian w/o Al


Lifetime - Q.E. vs wavelangth -Q.E. after lifetime test　(Ratio of Q.E. btw. before,after)

Large Q.E. drop at longer wavelengthNumber of Cherenkov photons；only 13% less (HPK w/Al)

Number of generated Cherenkov photon:~1/λ2

10-2

10-1

1

10

200 300 400 500 600 700 800 900λ(nm)

Q.E

.(%

)

HPK w/ AlHPK w/o Al

BINP w/ Al (#32)BINP w/ Al (#35)BINP w/ Al (#38)BINP w/o Al (#6)BINP w/o Al (#11)BINP before

HPK before

10-3

10-2

10-1

1

200 300 400 500 600 700 800 900λ(nm)

Rel

ativ

e Q

.E.

HPK w/ AlHPK w/o Al

BINP w/ Al (#32)BINP w/ Al (#35)BINP w/ Al (#38)BINP w/o Al (#6)BINP w/o Al (#11)


0

0.25

0.5

0.75

1


Rel

ativ

e G

ain

Time in Super-B factory (year)0 5 10 15

Lifetime - Gain -Estimate from output charge for single photon irradiation

<1013photons/cm2

Drop fast

>1013photons/cm2

Drop slowly

Single photon detection: OKCan recover gain by increasing HV



0

20

40

60

80

100


TT

S(p

s)Lifetime - T.T.S. -

Time resolution for single photonNo degradation!Keep ~35ps

Russian w/o Al (#6)

HPK w/o Al

Russian w/ Al(#32)

HPK w/ Al

－before－after

σ=31psσ=36ps

σ=43psσ=32ps

σ=34psσ=34ps

σ=29psσ=33ps



Multi-anode MCP-PMT (1)

NoAl protection layer

2Number of MCP stage

4 channel linear arrayAnode

27.5 x 27.5 x 14.8 mmSize

22 x 22 mm(64%)Effective area

0.3 mmAnode gaps

5.3 x 22 mmAnode size (1ch)

~60%Aperture

10 µmMCP Channel diameter

~20%(λ=350nm)Q.E.

Multi-alkaliPhoto cathode

R&D with Hamamatsu for TOP counter

SL10

• Large effective area 64% by square shape• Position information 4ch linear anode (5mm pitch)

22(effective area)27.5mm

1ch

2ch

3ch

4ch


Multi-anode (2)Single photon detectionFast raise time: ~400psGain=1.5x106 @B=1.5TT.T.S.(single photon): ~30ps @B=1.5TPosition resoltion: <5mmCorrection eff.: ~50%

Nucl. Instr. Meth. A528 (2004) 768.

Basic performance is OK!Same as single anode MCP-PMT

Raise time～400ps

tdc(time walk collection)

0

1000

2000

3000

4000

5000

6000

-25 -20 -15 -10 -5 0 5 10 15 20 25

ID

Entries

Mean

RMS

3542

19316

1.479

4.464

319.3 / 9

Constant 4725. 52.34

Mean -0.5600 0.1162E-01

Sigma 1.150 0.8783E-02

1bin/25ps

coun

t

T.T.S.: σ~30ps


Rate dependenceGain vs. photon rate

For high intensity beamGain drop for high rate

>105 count/cm2/sDue to lack of elections inside MCP holesDep. on RC variables

10-2

10-1

1

1 10 102

103

104

105

106

107

108

109

SL10HPK6BINP

Ndet(count/cm2/sec)

Super B-factory@L=2x10 /cm /sec

35 2

Rel

ativ

e G

ain

24~393116MCP capacitance (pF/cm2)

380~100014396MCP resistance (MΩ cm2)

BINPHPK6SL10

MCP

MCP channel

ElectrodeEnough for TOP counter


Applications

5ps TOFTOP counter


0

200

400

600

0 0.1 0.2 0.3 0.4

Arb

itrar

y sc

ale

0

10

20

30

40

Arb

itrar

y sc

ale

0 2 4 6Emission and propagation time (ns)

High resolution TOFStructure

Small-size quartz (cm~mm length)Cherenkov light (Decay time ~ 0) extremely reduce time dispersion compared to scintillation (τ ~ ns)

MCP-PMT (multi-alkali photo-cathode)TTS < 50ps even for single photongives enough time resolution for smaller number of detectable photons

Cherenkov light

Scintillation (BC408)Test counter

Simulation

Nγ~240

Nγ~820


Beam testMCP-PMT (HPK6, R3809U-50-11X)

TTS: ~30ps6µm hole

Readout electronicsσelec.: 4psTime-correlated Single Photon Counting Modules (SPC-134, Becker & Hickl GMbH’s)

CFD, TAC and ADC Channel width = 813fsElectrical time resolution = 4ps RMS


Beam test setup3GeV/c π− beam

at KEK-PS π2 line

PMT: R3809U-50-11XQuartz radiator

10φx40zmm with Al evaporation

0

100

200

300

40 80 120

4.1ps

Even

ts

TDC (ch/0.814ps)

BeamTrig.1

Trig.2TOF1 TOF2

30cm

Trig.1 Coinc. Discri.Divider

Trig.2

TOF2

TOF1PowerSpliter

Discri.

Discri.Divider

Start Stop

π, 3GeV/c-

SPC-134

Elec. resolution


Beam test setup photo


Beam test resultWith 10mm quartz radiator

+3mm quartz windowNumber of photons ~ 180Time resolution = 6.2psIntrinsic resolution ~ 4.7ps

Without quartz radiator3mm quartz windowNumber of photons ~ 80

Expectation ~ 20 photo-electrons

Time resolution = 7.7ps

Even

ts

100

200

300

400

40 80 120 1400TDC (ch/0.814ps)

6.2ps

100

200

300

40 80 120 1400

TDC

7.7ps

(ch/0.814ps)

Even

ts


TOP counter in Super B-factory

2.6m

1.2m

e-

8.0GeVe+

3.5GeV

TOP counter

I.P.

Side view of Super Belle

TOP counter should be compact!


~400mm

Linear-array type photon detector

LX

20mm

Quartz radiatorx

y

z

TOP counterCherenkov ring imaging using timing information

Difference of path length→ Difference of time of propagation (TOP)

150~200ps from TOP + TOF from IPwith precise time resolution (σ~50ps) for each photon


ChromaticityDetection time is depending on the wavelength of Cherenkov light.

Due to light propagation velocity depending on the wavelength.Time resolution become worse.

→ Separation of TOP ring image become worse.

300

400

500

600

16000 20000 24000 28000

TDC(ps)0

100

200

16000 20000 24000 28000

λ(nm

)

π, 2GeV/c, θ=90deg., ch=40

0.19

0.2

0.21

300 400 500 600 700Wave length (nm)

Gro

up v

eloc

ity (m

/ns) Light propagation

velocity inside quartz


Focus Mirror

y

PM

TFocusing TOPChromatic effect makes ~100ps fluctuation for TOP.Use λ dependence of Cherenkov angle to correct chromaticityFocusing system to measure θc

λ θc y positionReconstruct ring image from 3D information (time, x and y).

Focus Mirror

))(1

(cos=)( 1

βλnλθ c

ー

Rotate PMT

Side view

Mirror image


Focusing TOP (2)

1850mm

Virtual readout screen22mm x 5mm matrixFocusing

mirror

∆θc~1.2mrad

Use λ dependence of Cherenkov angle to correct chromaticity

Good separation even with narrow mirror and readout plane because of long propagation length

π/K sep.: 3.8σ 4.3σ for 4GeV/c


SummaryMCP-PMT studies

Good time resolution of ~35ps for single photonEven under B=1.5T

Gain~106 with <10µm MCP holeLong lifetime (<10% QE drop) until 3x1014photons/cm2

Gain degradation if Ndet >105 counts/cm2/sEnough performance for TOP counter in super B factory

ApplicationsTOF counter with quartz

5ps intrinsic time resolution in beam testTOP counter

To reduce chromatic error, introduce compact focusing mirror.Focusing type improves π/K separation in Super Belle.

Timing properties of MCP-PMT - Nagoya University · Timing properties of MCP-PMT K.Inami (Nagoya...

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